In the late 1960s Lin was openly described as Mao's deputy and heir, but the ageing Mao was growing increasingly paranoid and took offence at Lin's attempts in 1970 to persuade Mao to fill the position of Chairman of the People's Republic of China (ie titular head of state) which had been vacant ssince the fall of Liu Shaoqi and which Mao sought to abolish in a redrafting of the Chinese constituation. Relations between the two men deteriorated and what happened in the last days of Lin's life remains unclear.

What is known is that on 13 September 1971 Lin, his wife, and his son Lin Liguo, a senior air force general, fled their holiday home at Beidaihe in Hebei province to a nearby air force base, comandeered a VC10 aircraft and flew to the north west, towards the USSR, where Lin had solid contacts having spent much of the Second World War years there. It seems that the plane had not been fully fuelled, and it crashed in Mongolia killing all on board.

The official Chinese version of events is that Lin and his son had been plotting a coup d'etat against Mao called 'Plan 571' (in Chinese, the numbers 571 are spoken wu-qi-yi, which can also mean 'armed uprising'); and it was alleged that air force aircraft had mounted an unsuccessful attack against Mao's personal train. Lin's daughter, Lin Doudou, revealed the plot to prime minister Zhou Enlai, whereupon the plotters fled.

More recently, a history by Australian academics Frederick Tewes and Warren Sun has convincingly argued an alternative explanation, which is that 'Plan 571' never existed and that Lin fled because he was afraid of being purged and imprisoned by the increasingly capricious and paranoid Mao, and that he would not survive the prison conditions meted out to victims of the Cultural Revolution (indeed, the former Chinese head of state Liu Shaoqi had died in prison as a result of ill treatment and medical neglect). Teiwes and Sun draw attention to a recent thaw in Chinese portrayals of Lin: from being an 'un-person' he is now the subject of sympathetic biographies and memoirs, and his image was even included in a series of postage stamps commemorating Marshals of the People's Liberation Army.